Dear Sawada-san, > On Tue, Nov 28, 2023 at 7:04 PM Hayato Kuroda (Fujitsu) > <kuroda.hay...@fujitsu.com> wrote: > > > > > > Yeah, we followed binary_upgrade_create_empty_extension(). Also, we set as > > un-strict to keep a caller function simpler. > > > > Currently get_old_cluster_logical_slot_infos() executes a query and it > > contains > > binary_upgrade_logical_slot_has_caught_up(). In pg_upgrade layer, we > assumed > > either true or false is returned. > > > > But if proisstrict is changed true, we must handle the case when NULL is > returned. > > It is small but backseat operation. > > Which cases are you concerned pg_upgrade could pass NULL to > binary_upgrade_logical_slot_has_caught_up()?
Actually, we do not expect that it won't input NULL. IIUC all of slots have slot_name, and subquery uses its name. But will it be kept forever? I think we can avoid any risk. > I've not tested it yet but even if it returns NULL, perhaps > get_old_cluster_logical_slot_infos() would still set curr->caught_up > to false, no? Hmm. I checked the C99 specification [1] of strcmp, but it does not define the case when the NULL is input. So it depends implementation. [1]: https://www.dii.uchile.cl/~daespino/files/Iso_C_1999_definition.pdf Best Regards, Hayato Kuroda FUJITSU LIMITED
